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Scientists Growing New Crystals To Make LED Lights Better
coondoggie writes "When to comes to offering warm yet visually efficient lighting, LEDs have a long way to go. But scientists with the University of Georgia and Oak Ridge and Argonne national laboratories are looking at new family of crystals they say glow different colors and hold the key for letting white LED light shine in homes and offices as well as natural sunlight."
A little talk about UV LEDs and fluorescent materials, but not much talk about wide-band color phosphors, or even what bare LEDs to mix to match sunlight or what all. Seriously minimal content in the pointed to article.
The group has been studying the atomic structure of the materials using x-rays from Argonne's Advanced Photon Source. Two of the three types of crystal structures in the group of phosphors had never been seen before, which can probably be attributed to the crystals' small size, Budai said.You'd think they might actually mention what it is about the two crystal structures that has never been seen before !!! That might make it more interesting. There's not even a pointer to another web page or article that has details about this!!!! How disappointing.... editors, j'accuse! add a little substance, pick something more meaty !!!
These LEDs don't appear to be organic at all. We (I did my master's growing inorganic semiconductor crystals) say the crystals are "grown" because they are assembled typically atomic-layer by atomic-layer.
That said, this is a pretty terrible article. It doesn't say what method of growth they used, what they SAW from the growth, or really much about their experiments at all.
Stop right there. Have these people used recent LED lighting? I just upgraded some lights in my house to LEDs, and they're great. They're at least as good as the LED tubes they replaced, and that's at just over 100 lumens/watt. There are a lot of low quality LEDs out there, but the good ones are already very good indeed.
There's no point in questioning authority if you aren't going to listen to the answers.
When to comes to offering warm yet visually efficient lighting, LEDs have a long way to go.
What would visually-efficient lighting look like? Would it not be so time consuming to watch?
As far as warmth goes, there are plenty of options for warm LED light bulbs right now:
I have two of these 2700K bulbs installed in the ceiling fan here in my living room. I have no complaints about the light they provide, and the cost savings are significant. A warm bulb is not what you want in every situation... warm is good in a relaxing environment like the living room or bedroom, but in the kitchen and bathroom I have 5000K (Daylight) LED bulbs.
As far as them having "a long way to go," that sounds like what someone would say if they were trying to sell us some "new" unspecified kind of LED that they are only able to claim is better because not enough people have LED bulbs now to know they don't suck. Perfectly happy with mine. The only thing the manufacturers need to do now is bring the price down to drive wider adoption. Tell me this "new LED technology" will do that and you have my attention.
I was under the impression that the issue of translating LED light into a broad swath of color was an already solved problem (except for some fine-tuning optimization), using appropriately-sized nanoparticles which hand the energy from the photons around, slicing-and-recombining energy from photons into different sized packets and re-emitting the light at a frequency characteristic of the size of the nanoparticle. Cover the LED with a bunch of these in a range of sizes and you get a smooth spectrum.
Works the other way, too: Coat a solar cell with such particles and they take the random-frequency photons from the sun and slice them up into multiple new photons at a frequency good for the solar cell bandgap, and mash the levtovers into more big photons to re-slice to the correct size. (It's not 100%, since some of the photons get away. But it's more than a 2x improvement over a bare cell, which only takes one slice off each photon and throws the rest away.)
If this is correct, this project looks like just a fine-tuning of making the nanoparticles, or finding materials for them that are somewhat more efficient than what was already being used (which was pretty good).
I haven't been following this all THAT closely. Have I misunderstood the current stuff? Or is this just a little incremental tweak along the cutting edge?
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way